Venter has hailed artificial life forms as a potential remedy to illness and global warming, but the prospect is highly controversial and arouses debate over its potential ramifications and the ethics of engineering artificial life.

The J Craig Venter Institute announced earlier this year that they had succeeded in synthetically reproducing the DNA of a simple bacterium.

The researchers had initially used the bacteria E. coli to build the genome, but found it was a tedious, multi-stage process and that E. coli had difficulty reproducing large DNA segments.

Recombining genes

They eventually tried using a type of yeast called Saccharomyces cerevisiae, also known as baker's yeast.

This enabled them to finish creating the synthetic genome using a method called homologous recombination, a process that cells naturally use to repair damage to their chromosomes.

According to the Institute the capacity for DNA assembly in yeast turned out to be a "genetic factory".

The researchers inserted relatively short segments of DNA fragments into the yeast cells.

They found they were able to build the entire genome in one step.

"We continue to be amazed by the capacity of yeast to simultaneously take up so many DNA pieces and assemble them into genome-size molecules," says lead author Daniel Gibson.

"This capacity begs to be further explored and extended and will help accelerate progress in applications of synthetic genomics."

Senior author Dr Clyde Hutchison says, "I am astounded by our team's progress in assembling large DNA molecules. It remains to be seen how far we can push this yeast assembly platform but the team is hard at work exploring these methods as we work to boot up the synthetic chromosome."

Synthetic genome

Venter and his team continue to work towards creating a living bacterial cell using the synthetic genome sequence of the Mycoplasma genitalium bacteria.

The bacteria, which causes certain sexually transmitted diseases, has one of the least complex DNA structures of any life form, composed of just 580 genes.

In contrast, the human genome has some 30,000.

Using the genetic sequence of this bacteria, the Maryland-based team has created a chromosome known as Mycoplasma laboratorium.

They are working on developing a way to transplant this chromosome into a living cell and stimulate it to take control and effectively become a new life form.